US 2738313 A
Description (OCR text may contain errors)
March 13,1956 J. MILLER 2,738,313
METHOD AND APPARATUS FOR PRODUCING ASPHALT Filed July so, 1952 IN VEZV TOR. w 74 Z/m United States Patent METHOD AND APPARATUS FOR PRODUCING ASPHALT James Miller, Palos Park, Ill.
Application July 30, 1952, Serial No. 301,620 7 Claims. Cl. 196-7 4) The present invention relates to an improved process and apparatus for converting base crude materials into asphalt.
The production of asphalt by the partial oxidation of oily and bituminous materials is an old art, which has been practiced for a great many years, the basic principle involving the blowing of an oxidizing gas through the material at an elevated temperature.
The earliest methods involved merely theheating of oily residues, particularly petroleum derivatives, to a high enough temperature to drive therefrom substantially all of the volatile material which may escape below the ignition point of the material. However, in order to produce a finished material of acceptable quality, it was found necessary to at least partially oxidize these residual tars and pitches produced by the distillation of petroleum products so as to give them certain qualities relative to their solubility, softening point, ductility, penetration or hardness, and the like, so that the finished product would meet commercial specifications.
When blowing these base crude stocks to produce asphalt there was always the danger, caused by the mixture of oxygen with the volatile materials released, of reaching the flash point in which case there could be serious consequences, because the tank or other vessel containing the material would tend to ignite and possibly explode.
Accordingly it is one of the objects of the present invention to provide a method and a suitable apparatus whereby it is possible effectively to convert base crude materials such as petroleum residues, pitches, tars, and the like, into commercial asphalt with an improved economy and without danger of explosion.
A further object of the present invention is to regulate the temperature and nature of the gases which are passed through the material which is to be converted so as to operate at all times at the optimum temperature, but preferably just short of the flash point of the material and the vapors evolved therefrom.
late-the temperature of the gases employed by cooling them by 'evaporative cooling, as for example by injecting a volatilizable liquid thereinto, and to employ these cooled gases to reduce or control the temperature of the materials being treated. Products of combustion at temperatures lower than that of materials being processed may also be used to control or cool the materials.
A further object'of the present invention is to provide an apparatus in which the pipe through which the hot gases areintroduced is jacketed or shielded from the com- -rnon vapor space of the vessel in which the operation ftakes place, so that the vapors will not be ignited by the 2,738,313 Patented Mar. 13, 1956 high temperature to which said pipe becomes heated by reason of the passage therethrough of the hot gases.
Further objects of the invention will become apparent from the further description herein below when considered in connection with the drawings.
Figure 1 is a side elevational view with some parts in section where necessary for proper explanation thereof; and
Fig. 2 is a detail, on an enlarged scale.
Referring now to the drawings, there is provided a vessel or asphalt-blowing tank 1, which is supported upon foundation 2. An inlet pipe 3, provided with a suitable valve 4, serves to introduce the oily material into the vessel 1, so that it may be filled to the extent of about three quarters of its capacity, preferably to a definite liquid level 5.
Located and laterally extending along the bottom of the tank are a plurality of perforated pipes 6, 7 and 8 which are operatively connected with the main blowing pipe 9, which has a portion 10 extending vertically downwardly into the vessel 1 through a well 11 which is in the form of a pipe integrally welded to the walls of the vessel 1 at the point 12. This well 11 has an inside diameter several inches larger than the outside diameter of the portion 10 of the pipe 9 and preferably but not necessarily has an upwardly and outwardly extending funnel 13 at the top thereof.
It will thus be seen that the portion 10 of the pipe 9 will not be in contact with any of the vapor in the vapor space 14 of the vessel 1 so that irrespective of what temperature it might attain, the vapor will not be ignited as a result of the contact with the portion 10 of pipe 9.
There is also provided a relatively large vapor line 15 which extends from a small dome 56 at the top wall of the vessel 1, this vapor line 15 extending into a vertically positioned washer vessel 16, the extension 17 of the pipe 15 extending below the water level of liquid such as water 18 contained in the bottom of the washer 16. A suitable pipe 19 and valve 20 serve to drain this vessel while from the top thereof there extends a gas line 21 which, if desired, may be either vented to the atmosphere or may lead to suitable condensing instrumentalities which are now shown and form no part of the present invention.
The means employed for obtaining and introducing the oxidizing gas into the liquid comprises a rotary air pump 23 from which a pipe 24 extends to a heater 25.
An intermediate control gate valve 26 is provided in the pipe in order to control the flow of air therethrough. The heater 25 is merely a hollow shell lined with fireproof material such as fire brick or ceramic lining and within it is positioned an ordinary gas burner (not shown) which is fed with gas through the pipe 27. A suitable sight glass 29 may be provided so that the proper functioning of the burners may be observed. The only air for blowing and combustion is provided by the air pump.
The resulting very hot combustion gases leave the heater 25 through the pipe 30 and enter a temperaturecontrolling vessel 31. This vessel is provided with a thermorneter 32 and also with a water spray head 33 which is supplied with water through the pipe 34, the flow being controlled by the valve 35.
A clean-out flange 36 is also provided at one side of the temperature controlling vessel 31, which also has at the bottom thereof a sump 37 provided with an automatic float discharge mechanism contained within the housing 38 through which water may be educted through the tail pipe 39, and the hot mixture of gases enters the vessel 31 through the line 30. The temperature is observed on the thermometer 32 and if it be too high a suitable amount of water is sprayed into the vessel through the spray head 33, thereby cooling the gases by reason of the evaporation of all or part of the water sprayed into the vessel,
Any water which is not vaporized will collect in the sump 37 and eventually is discharged through the line 39. The mixture of hot gases and water vapor then passes upwardly outof the vessel 31 through the aforementioned line 9, and hence passes eventually through the pipe and the branch perforated pipes 6, 7 and 8 into the mass of material contained in the blowing vessel 1.
In order to provide means for emptying the vessel 1 at the close of the operations, a discharge pipe 41 and discharge valve 42 are provided but these remain closed during the operation. I
The operation of the aforementioned apparatus is substantially self explanatory on the basis of what-has just been said, but it might be stated that the temperature of the gases which are allowed to pass through the liquid 40 should preferably be not greater than the flash point of the liquid, although with the reduced oxygen content, higher temperatures can be countenanced with less danger than heretofore. Therefore, as the amount of volatiles decreases, the temperature may gradually be raised. By reason of the fact that these temperatures are quite high and may be on theorder of from 600 to 700 F., it will be evident that were it not for the provision ofthe wall or jacket 11, the portion 10 of the pipe which passes through the vapor space 14 might reach a point which would produce a flash of the vapor in the space 14, with highly undesirable results. 7
There will of course be a small amount of vapor in the annular space between the wall or revent 11 and the pipe 10, and if such vapor should become ignited it would find immediate means to escape through the funnel 13 through which it could flash upwardly into the atmosphere without damage or harm.
This particular method of introducing the hot gases is considered to be one of the important features of the present invention, the other important feature lying in the means forcontrolling the temperature of the gases by the water spray.
' The present method and apparatus-are suitable for the conversion of cracking still residues, residues from the distillation of crude petroleum and other forms of tars and pitches into asphalt, but the invention is not to be limited to the employment of any particular type of productcapable of being thus partially oxidized.
It hasalso been found that once such oxidation is well under way, it is possible to operate with the burners in the heater 25 shut off, and with the water spray also shut off, and merely pumping air through the material from the pump 23 and through the line 10 and the branch pipes 6, 7 and 8 into the material which is undergoing treatment. action in many cases is capable of supplying suflicient heat to maintain the operation until the blowing iscompleted.
If desired, a check-valve 28 may be provided in pipe 9. This may be of usual construction. For example, as shown in Fig. 2, it may include a liftable flap connected to a rod 46 which is secured to lever 47 carrying a weight 48 slidable thereon and secured, when in des red position, by the screw 49. Stops 50 and 51 serve to limit the movement of the flap. The pressure of the air being blown in by the pump 23 is great enough to lift the flap, but when the pump either stops or supplies-insufficient air, the weight will cause the flap toclose and thus seal off the pipe 9. i
The function of the washer 16 is to remove any easily eondensible material and of course also the water which is present in the form of water vapor. This washer may, if desired, be additionally provided with cooling means, but all this is well within the known skill of the art, and no claim is laid to any novelty and to that portion ofthe apparatus.
Accordingly, what it is desired toclairn as newis:
1. Apparatus for blowing asphalt comprisingavessel for holding molten bituminous material, means for in troducing gaseous fluid thereinto consisting of a vertical pipe and perforated branch pipes connected therewith,.
The exothermic nature of the oxidizing re- 4 and a jacket for said vertical pipe spaced therefrom and open at both ends, the lower end thereof being below the intended level of the material and the upper end in open communication with the atmosphere.
2. In an asphalt-blowing apparatus consisting of a horizontally disposed tank and a vertical pipe having horizontal perforated branch pipes for introducing a gaseous fluid into bituminous material contained in said tank below the surface of the material, the improvement comprising means for preventing ignition of combustible vapors arising from said material which means consist of a larger open-ended conduit surrounding said vertical pipe and peripherally spaced therefrom, with the lower end of said conduit being located low enough to be submerged in saidbituminous material and the upper end being in open communication with the atmosphere.
3. Apparatus for converting heavy bituminous material into asphalt which comprises a vessel for holding a mass of such material, perforated pipes arranged in the bottom of said vessel for conducting gases into said material, a vertical gas-supplying pipe connected with said perforated pipes and extending outside of said vessel, a tubular jacket for said pipe open at both ends and of an inside diameter greater than the outside diameter of said vertical pipe so as to be concentrically spaced therefrom, the lower end being adapted to dip below the surface of the material contained in the vessel, and means for heating a supply of a gaseous fluid and for forcing it through said vertical pipe into said perforated pipes.
.4. Apparatus as defined in claim 3 in which means are provided for controlling the temperature of said gaseous fluid.
I, 5. Apparatus as defined in claim 4 in which the means for controlling the temperature of said gases comprises a water spray.
6. Apparatus for converting heavy oily material into asphalt which comprises the combination of an air pump, meansfor heating air pumped thereby including a burner andmeansfor blending the combustion products thereof with said air, means for regulating the temperature of the resulting gaseous mixture comprising means for spraying water into the mixture, whereby to add steam thereto; a tank for holding an oily material which is to be converted into asphalt, and conduit means for forcing said gaseous mixture into said material below the surface thereof, said conduit being located in part within said tank, the part thereof in the tank being surrounded by a somewhat larger open-ended jacket the lower end of which is positioned so as to be below the level of the material in the tank and the upper end being open to the atmosphere, the outer surface of said jacket being joined to the wall of said tankto make a hermetically tight seal therewith; means for educting vapors and gases from said tank, and means for-washing the same; and means for discharging asphalt from said tank.
7. 'In aprocess of blowing asphalt and the like in, which a highly heated gaseous-mixture is introduced in a vessel into'a liquid mass of inherently combustible material below the surface thereof through a pipe passing through the space above said liqnidand where the temperature of said pipe, by reason of the temperature of the gases, may beabove theflash-pointof the said liquid mass, the method of preventingexplosion ofvapors arising fromsaid liquid whichcomprises shielding. said pipe from said vapors by anair-jacket open at both ends, with its lower-end submerged in said liquid, and its upper end open to the atmosphere.
References Cited in the file of this patent